Helping people with computers... one answer at a time.

Flash memory is not the same as the type of memory used as your system RAM. They have different characteristics and they're accessed differently.

Can I use a USB RAM stick to increase system memory?


That was simple. But to avoid this becoming the shortest Ask Leo! article ever, let me explain why.

As you can probably guess by now, all memory is not created equal. Your system memory typically resides on your computer's motherboard, and uses a very high speed interface to connect to your computer's CPU. In fact, as fast as that interface is, it's still not as fast as we would like it (so true about so many things), and most modern CPUs actually copy or "cache" blocks of memory internally where they can access it even faster.

One of the characteristics of system memory is that when you remove power, *poof*, the memory has lost whatever it contained. Time to reboot.

"The downside to flash RAM is that it's slower."

USB Memory Sticks, on the other hand, are expected to retain whatever you put in them when the power is removed. Heck, they're expected to retain their memory when they're completely removed from the computer. As a result they use a different memory technology typically called "flash ram", which does exactly that. It's called "flash" because the memory contents are loaded, and then a special signal is sent that, in a sense, tells the memory to "remember this, now". It's kind of like taking a picture with a flash on your camera ... the picture "remembers" the state of everything when the flash went off. Flash BIOS is called that for the same reason - it's just flash memory that contains your computer's BIOS.

The downside to flash RAM is that it's slower. Reading flash memory is slower, and writing to flash memory is MUCH slower. It works fine as a virtual disk drive because our expectations for a disk's speed are quite different than what we expect for system memory.

In addition to the issue of the memory's own speed, there's also the USB interface to consider. As fast as it is for other purposes, it, too, is significantly slower than your system's main memory.

So USB RAM sticks, memory sticks, key chain drives, geek sticks, whatever you call them, are great for portable data storage. But increasing your system's memory is an entirely different proposition.

Article C2327 - April 9, 2005 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

June 1, 2005 6:10 AM

Well Leo,

I was quite interested by this article. But the final statement "But increasing your system's memory is an entirely different proposition" does nothing to conclude WHY they can't be used.

If anything it suggests there IS a way to do it, but it's different to using conventional RAM. I expected that much. Then I expected there to be an explaination of how to do it.

Sure USB Memory Sticks are slower, but they are still memory. So why can't they be used?


June 1, 2005 9:36 AM

Because they are not connected to the high speed memory buss (the physical connection) that goes to the processor. It's physically impossible to use them as additional computer memory.

Sorry that wasn't clear.

June 9, 2005 8:42 PM

simply because they cannot be used in directly the same way as conventional RAM could a USB Flash drive not be used as swap space? in using it that way you could 'virtually' increase your system memory could you not?

June 9, 2005 8:48 PM

I don't believe Windows will allow you to place the swap file on a removable drive, which is what a USB drive is treated as.

August 15, 2005 4:46 PM

Wait for Windows Vista. :-)

October 9, 2005 2:31 AM

I was doing research on this subject quite a while back and came across a site that explained how to use a flash drive as a swap on windows. It explained how to create boot sectors on the drive, also how to trick the system into reading the geek stick as a fixed drive. However, the transfer rates were MUCH slower than your pc's HDD, therefore you are much better off using a third party partition software to put a virtual drive at the BEGINING of the HDD. Windows rescue disk partition software doesnt allow you to put the virtual partition at the beginning of the drive to my knowledge. A good method of doing this for free is to order some LINUX boot cd's from (order 20). Their partition software allows you to create FAT16, and FAT32 partitions for windows9x. First create a FAT16 or 32 logical (virtual) drive. It may ask if you want it at the beginning or end of the drive, USE BEGINNING. This is important because the HDD can read info. from this area the fastest, because it doesnt have to move as much to access the swap. The swap area should be about 10% of your total disk space (eg. 8GB HDD should use a 800MB swap). After your swap is created, create your standard boot partition. Simple, NO? YES! Note: Creating a logical drive for your swap will speed up app. start time by my guess would be 10%. Placing the logical drive at the beginning of the HDD 15% or 20%. If you have alot of ram, instead of using this area to swap, use it for temporary internet files for netscape or IE6 (on netscape goto preferences, and on the left side go to advanced, then cache, then choose folder.)(on IE6 in internet options go to temp. internet files, settings, then move folder). You can even create a swap partition and a temp. internet partition at the same time on a low ram pc. If you do this, be sure to defragment this area often. This gives you a signifigant boost in web page load times. The more often you defrag, the faster pages will load. This is one area of windows that you can REALLY notice the difference after defraging. Happy surfing everybody, have fun with this info :-)I know I do.

Mathew Rennie
October 15, 2005 11:34 PM

Hi Leo,

I was intrested in your artical and thought I would give it a read. I'm surprised to learn that someone of your own knowledge can clearly say no to something that Microsoft is currently building/investing into their Windows Vista software.

Anyway something for you to read up on..

Mathew Rennie


November 30, 2005 12:52 PM

I have 2 mem sticks for a HP Pavilion a707. I only have one spare slot. Is it possible to buy an 'adaptor' that would allow me to plug the 2 sticks into the 1 port?

December 7, 2005 10:22 PM

No. You're limitted by the capacity of the motherboard.

December 26, 2005 1:49 AM

Microsoft has implemented similar software in its Windows Vista operating system which allows users to convert there USB Flash drives into additional system memory. Why is it that your own knowledge apparently contradicts the claims of one of the worlds largest software vendors?

January 4, 2006 2:52 PM

Why does his answer contradict? SIMPLE! Windows Vista is not released yet, therefore there is no CURRENT way of using a USB flash drive as system memory. When Vista is released, maybe there will be, but until its official release, Leo is 100% correct, no way to do it, so there =

January 4, 2006 9:30 PM

That, and because of how the CPU actually physically accesses system memory, I think it's highly unlikely that a USB interface could be used to expand it. I'm looking forward to seeing exactly whatever it is that Vista supposedly does.

February 19, 2006 8:17 AM

You could use like 4 flashdisks in a raid system.. that'd speed things up.. :P

February 20, 2006 12:46 PM

hi Leo
i would like to know how i can make flash o ram disk on my usb key .

I have a usb phone with 128 mb of memory built in, now i whant to put the driver i wrote on (that use java) but i really want to have all environment on RAM DISK o FASH on USB memory for do not get windows error if i unplag it !

any suggestion are welcome

March 30, 2006 8:49 PM


USB flash drives can be used as External Memory Devices (EMDs) to extend system memory and improve performance without opening the box. Your computer is able to access memory from an EMD device much more quickly than it can access data on the hard drive, boosting system performance. When combined with SuperFetch technology, this can help drive impressive improvement in system responsiveness.

EMD technology is both reliable and secure. You can remove an EMD at any time without any loss of data or negative impact to the system; however, if you remove the EMD, your performance returns to the level you experienced without the device. Wear on the USB drive is not an issue when using it as an EMD. A unique algorithm optimizes wear patterns, so that a USB device can run as an EMD for many years, even when heavily used. Finally, data on the EMD is encrypted to help prevent inappropriate access to data when the device is removed.

May 10, 2006 8:26 AM

Quote- "hi there can you tell me my computer is under warranty so dont want to start taking it apart can i get more ram from a usb cause my computer is realy slow at the minute or could you tell me how to speed it up"

You're not going to void your warranty by adding more RAM. Also did you not read the article?? It quite clearly says NO you can't use a USB flash drive as RAM! Also learn how to write properly, what are you, like 10?

May 30, 2006 3:20 PM

The flash memory is for vram, not to add ram.

June 9, 2006 2:25 AM

Actually you can use a flash drive for virtual memory under windows already. I have a 128mb flash drive that I have set up with a pagefile so it acts like virtual RAM - it helps because it is a dedicated drive and doesn't eat into the builtin hard drive in my laptop.

Leo A. Notenboom
June 9, 2006 10:49 AM

Perhaps, but I wouldn't do it for two reasons:

b) if it were unplugged accidentally, it could be disasterous for whatever you were doing at the time

Rob Marmion
July 13, 2006 5:18 AM

I'm looking for a performance comparison of the performance (data transfer speed, throughput etc) of using a USB stick as a hard drive vs using a regular hard drive.
Crasher-Link made a tantalizing reference to the fact that USB sticks were much faster than hard drives, but I'm looking for confirmation and numbers. Can you help?
Thanks, Rob

August 11, 2006 10:50 PM

WINDOWS VISTA HAS AN AUTORUN FEATURE (the little screen that appears when you plug in a flash drive or insert a cd, on xp) THAT LETS YOU IMPROVE RAM WITH YOUR FLASH DRIVE!!! Although when I switched back to XP, yes the ram was still there in a *.sys* file. The only difference between internal computer flash and flash drive memory is that flash drives of any type "WRITES" the ones and zeroes to the chip, internal ram "STORES" the ones and zeroes. Duhh...... even I knew that fact.

August 13, 2006 2:03 PM

Is that one guy bitter about flash drives??? He seem to the idea of using usb as ram and even lies to people saying it isn't possible. Has he heard of pagefiling? If you pagefile to ur usb memory it will increase the transfer speed than using the hard drive as well as allowing the information to go between both usb and the hard drive allowing for more information transfer. Too bad he is so stuck in his was he refuses to give people decent advice.

August 18, 2006 3:45 PM

Leo's answer is correct: No.

If the question was: Can I use a USB stick to speed up my computer, then "Posted by: Crasher-Link at March 30, 2006 08:49 PM" would be correct.

"Posted by: mike at April 25, 2006 11:28 AM" was actually a valid comment, as "mike" understood the question correctly, hence what sounded (to some) like a "childish" comment.

Most of the other comments miss the point of the question, or involve answering the wrong question.

No one yet has validly realised each erroneous answer, nor given credit for the contributions.

Eric Bergemann
November 10, 2006 11:13 AM

A Flash drive doesn't have much faster transfer rates than a hard drive, however, the underlying structure of a USB Flash drive allows for faster RANDOM access.

This means that if you had four programs reading from the flash drive at once versus four programs reading from a hard disk at once you would find that the flash drive is faster. This is because flash memory can just as easily read from the first byte as the last byte, however, a hard disk has to spin up and get to the other end of the disk and then go back and read from where it was before and then keep going back and forth... I often call that "Disk Thrashing". A USB flash drive can prevent "Disk Thrashing".

Another effect of using USB flash drive's on laptop's is that the battery life is longer. This is because it takes alot less energy to spin up the hard drive than to read from a flash memory block.

Windows Vista's ReadyBoost functionality will definately help speed up computer's when they are under a great deal of processing.

Don't discount the concept of using USB Flash drive's to increase system memory, they do have their place.

December 12, 2006 2:40 PM

The "Flash" part is NOT similar to a camera's flash. The camera use a flash to remember the picture. The flash in the flash drive is used to erase the data stored. Two small signals are need to change a 0 to a 1 but a large signal (the flash) is need to change 1 to 0, clearing the data stored.

December 12, 2006 2:45 PM

The Flash BIOS is so named b/c before the current flash ROMs that used electricity to erase data, they had to use real light flashes. In order to update the firmware you had to open your case and flash the BIOS before you are ready to load in a new version. The "flash" originated from the actual light flash that was used to earse old style ROMs.

January 29, 2007 9:35 AM

Vista will allow one to add usb ram to a system. Its called "ReadyBoost"

Leo Notenboom
January 29, 2007 9:49 AM

Hash: SHA1

ReadyBoost does not actually add to the available system RAM, but rather
adds the memory to Vista's new "SuperFetch" feature. You can read more
about ReadyBoost here: and SuperFetch


Version: GnuPG v1.4.6 (MingW32)


A Friend
March 23, 2007 1:30 PM

I found this at:


Using memory in your storage device to speed up your computer
Applies to all editions of Windows Vista.

[Copyrighted material remove. Click the link to see the full text being referenced. -Leo]

Leo Notenboom
March 23, 2007 6:38 PM

Hash: SHA1

And to be VERY clear, ReadyBoost does NOT add RAM to your system.

ReadyBoost adds something more like swap space from which applications can load
more quickly and which the operating system can use very much like vitual
memory on a hard disk.

Version: GnuPG v1.4.6 (MingW32)


May 14, 2007 4:38 PM

One other point on this is the limited read/write cycles that flash memory provides. Unlike real RAM Flash memory has limits on the amount of reads and writes that can be performed before the memory becomes unusable. The amount of cycles numbers in the multiples of thousands and works well for "Drive" type operation but would not work too well for RAM applications.


June 1, 2007 6:13 AM

I do ne tihs on my dell dimension 4550 using a 128mb usb flash drive, when i reset the computer i had to remove the drive and reinsert it as windows loads, otherwise the computer ignores it, so far im still fine tuning it because using to much of its memory would be bad for it and would be counter active.

im sure its working because its WARMING UP A LOT!

Roy Davis
June 20, 2007 6:27 PM

Dear Leo:

You're probably tired of this discussion, but I would like your thoughts on using a CF drive for virtual memory. Looking at 150X transfer speed (@20Mbps), WINDOWS XP OS. Also is there a XP equivalent of super fetch. Thx for your time.


Leo A. Notenboom
June 21, 2007 4:58 PM

Hash: SHA1

I sure wouldn't. You'll wear it out. See this article:

And, no, I'm not aware of an XP equivalent to Vista's superfetch.


Version: GnuPG v1.4.6 (MingW32)


Your Mom
October 28, 2007 10:16 AM

November 5, 2007 4:24 AM

You -can- use an USB stick as additional swapspace if you haven't a second harddisk for that purpose. The speed may vary from stick to stick and you probably want to use USB 2.0 hardware for that anyway.

When you use memory sticks of 1 GByte or more you do not need to worry too much about the "wearout" of the Flash cells. Most (all?) USB flash devices redistribute write operations internally so there will be no 'hot spot' where a single memory cell is changed ever and ever again.

Of course, swapspace is much slower then RAM (about 1000 times). But if you have to use swapspace a stick may be an alternative. The transfer rate of the stick may be slower than that of the normal harddisk. But that is not so worse because there are no mechanical components to be moved to access a data sector on the stick.


December 12, 2007 9:03 AM

ReadyBoost doesnt had extra RAM to your computers memory....but... applications can run commands and such off the usb drive saving your computers memory.

Essentially its the same thing. If your computer is crashing because your short a few 100 mb's of memory... readyboost will help out alot.

December 12, 2007 9:05 AM

spell check hehe previous post.. The 3rd word "had" is supposed to be add

January 21, 2008 2:36 AM

Please tell me how to use some of my hard disk space as RAM.

Leo A. Notenboom
January 22, 2008 5:41 PM

Hash: SHA1

That's what your system's virtual memory is, sort of.


Version: GnuPG v1.4.7 (MingW32)


March 24, 2008 4:49 PM

There is a way to get some RAM-ish functionality out of a flash drive, using Vista's ReadyBoost or the software from which allows XP users to do the same thing. Not RAM per-se, but it does allow stuff to load a WHOLE lot faster on my old machine (only half a gig of ram)

April 3, 2008 11:01 PM

I just loaded eboostr to my Toshiba Laptop and I see a tremendous difference. I was getting ready to give up on this thing. All programs were ultra slow, (Mozilla takes 5min to load). Now I can load most programs in seconds. Like having more RAM instantly. Thank you for the advice. This is a very great program as far as I can see.

April 12, 2008 1:48 PM

There is a third party program for XP called eBooster:
which promises great things by using a flash drive in a similar capacity to ReadyBoost (or so I`m lead to believe). I gave it a try with a 1 gig Memorex "Travel-Drive" stick and it didn`t actually make a terrific difference on my machine, although I thought that boot-up was a tad faster. Even now, I`m not absolutely sure what it does or how it works, if someone could enlighten me further. There`s lots of activity from the LED on the drive and I can view a whole load of cache data stored on it (which doesn`t mean a lot to me) but it was my understanding that these drives wear out and couldn`t be used in this way.

August 5, 2008 4:50 AM

How come my RAM amount didn't increase on the System thing?

Probably because you didn't read the article. USB ram sticks cannot and do not increase system memory.


September 26, 2008 2:21 AM

Frankly, the concept of placing vital bit information on to a detachable stick is not very bright. Imagine the damage you could do by simply pulling on the wrong stick. Hard disk transfer speeds are greater than that of USB so HDD virtual memory is probably the more superior option, especially if you have set your page file to be on a different drive to that of your OS. Also, I suspect that USBs non-volatile memory will give you less read/write cycles before destruction that volatile RAM (loses data on switch-off), supporting my earlier comment.
A USB root can support 127 devices. All the information for these devices is split and forced down the same line (serially). Ok, you may just have a mouse or keyboard but even this means that your USB RAM may not have priority and the time is certainly split between the devices. Say you are running a program and the data for it is divided between your onboard RAM and USB stick. The data it is looking for is on the stick and so, despite the fast speed of your RAM, your program will hang and wait for the data it requires from the stick. Everything will be running at stick speed. This can cause time-outs and freezes as the CPU will be demanding info that is not available due to the waiting times and priority of the USB root.
Using USB sticks for RAM also requires an alteration of your USB drivers. Consequently this can result in a massive heating effect which can cause the destruction of the stick and then, your OS installation/computer.
I advise to stay away from this quick fix until it has been researched and developed further. Opt for purpose built RAM, giving you speed and reliability.

Ken Gettys
November 9, 2008 2:31 PM

From Micosoft:
"Windows ReadyBoost improves system memory and boosts performance. The flash memory device serves as an additional memory cachethat is, memory that the computer can access much more quickly than it can access data on the hard drive. Windows ReadyBoost relies on the intelligent memory management of Windows SuperFetch and can significantly improve system responsiveness."

Ken Gettys
November 9, 2008 3:24 PM

After installing the 1GB USB flash stick (it is not ram) and setting up my Vista computer to use 350 mb of it as Memory Cache (again, not ram), I went to the Task Manager (via Ctl/Alt/Del) then to the "Performance" tab then to the "Resource Monitor" Button, then to the "Disk" Frame where I found that the "f:\ReadyBoost" drive\program had used 3,100,000 Read B/Min and 7,400,000 Write B/Min. This while I was only downloading Vista SP1 (large update) and IE 8 Beta for Vista (smaller update). Hard to tell if the 27 ms access time makes any over all difference as there were lots of small sized Page File disk references too. Closer monitoring (which I don't have time for right now) of this information may prove that using the Vista included Readyboost program and a flash drive might make a difference in providing faster accessable disk cache than hard disk page file access. While at breakfast at McDonalds I saw in a Target ad this morning for a 16gb flash stick for $49.xx which got me to think and then Google "USB Ram" to find another always friendly and often very helpful "Ask-Leo"'s blog!

December 6, 2008 6:28 PM

I understand what you say about the flash drive, statement by statement. But yourself point out that we consider the flash drive fast because for practical purposes its speed is comparable with that of a HD - and Windows has (always ? certainly for a long time) provided a way of assigning 'virtual memory', which must involve the HD spinning (spinning more). So it seems to me that in terms both of functionality, and of risk associated with increased wear and tear, the situation is much less absolute than you're painting it ?

I don't know, seems like there are some absolutes to me:

People are asking if flash memory can be used as system RAM. The answer is an absolute no.

People have wondered if flash memory could be used for Virtual Memory. In my opinion the answer is, once again, absolutely no, since that will cause the flash memory to wear out very quickly.

Window's Vista's "ReadyBoost" is a compromise - it's not RAM, and it's not VM, but it is flash memory used in a semi-intelligent manner to boost overall performance.
- Leo

david davis
December 27, 2008 3:48 AM


As a real world example, I overcame a problem with multi-track recording. The program needed access to my .wav file on the hard disk - at the same time it needed to write the live audio I was recording. There were skips and stutters as I recorded. To solve this problem, I simply moved my source audio .wav file, 60 Megabytes, to a 1 Gig USB key. Then reimported the .wav file from the USB key. This freed my hard disk from having to read and write simultaneously and the skipping stopped.

I am also using this technique to create overflow cache space for After Effects and Photoshop. The access speed is not as fast as RAM, as you say, but it is fast enough for caching current work and preview data.

Yep, that's a fine use for USB Flash Drives. But to be clear (and on-point for this article), it did not increase your RAM. In fact, you simply used it as an additional drive.
- Leo
January 15, 2009 3:44 AM

i have create a ramdisk as a removable drive(Media type--3). i want to use it as a readyboost. i have edited the registry key under EmdMgt and then restart the service readyboost. but the ramdisk was not configured as readyboost. if i do same for a flashdrve it works. manually it is possible to create readyboost in ramdisk by opening the property of ramdisk.please help me if it is possible to configure ramdisk as a readyboost by program.

ali zaman
January 31, 2009 3:11 PM

HI leo ! i just need to know that How can i use my 512MB or 1GB flash drive as a RAM ? please answer me on my mail ?

You cannot. Read the article you just commented on.
- Leo

Leo (how ironic)
February 15, 2009 4:01 AM

Hi Leo,

Thank you for your advice. I was about to go to the store to buy a USB stick to use as RAM after a widget I just downloaded is showing I'm using about 70-80% on average.

I was always reluctant to use USB devices for ayatem memory, but the price difference ($10 for the stick opposed to $50 for the 512MB of SDRAM) . Now my inner cheapskate is asking for a solution. How effective is virtual memory from the hard drive for being used as system memory and is there a cheap alternative method to getting more system memory?

Jenny Thompson
August 16, 2009 2:39 AM

Hi! Thank you for taking the time to help me but i have a memory stick that goes inside my desktop do i find out what kind and size it is? It has a few really long numbers on there a search engine that i can put one of the numbers(maybe one is a serial number) in and it comes back with type and speed? I hope u could give me pointers to locate the answer.

Janib Soomro
August 18, 2009 11:45 PM

Well, you can use USB stick for performance enhancement. I am using a software EBoostr, which layers between Harddish and RAM.

Copies contents from harddisk and saving them in USB and later providing the data to RAM. Dont know about others, but I am quite a fan and using my 4 GB USB.

Try it, i hope you find it too useful and CHEAP.

Rajesh Perumal
November 5, 2009 2:22 PM

U can use USB pendrive as RAM in Windows Vista & Windows 7. Read the full detailed explantion with screenshot on the link shown here

The article referenced discusses Windows 7's apparently increased ReadyBoost abilities. Nonetheless, ReadyBoost is not RAM. Period. It's nothing more then a glorified pre-load cache - reports of its effectiveness are mixed. You cannot use a USB pendrive to increase actual system RAM.

January 20, 2010 11:25 AM

Flash memory may not speed up your PC in general, but if you have an insufficient amount of internal RAM, Flash memory does help and actually makes your pc faster.

Vista and windows 7 have an integrated option to use a USB stick as RAM, called 'ReadyBoost'.

This option is freely downloadable for windows XP here.

February 9, 2010 9:34 AM

using usb as memory device... as a virtual ram...

Sounds like some people needs to go to google and search for pagefile.sys or win386.swp or many other things... pagin ram is an old thing... using an usb instead of a harddrive for paging (Yeap... google for it) is stupid, i can write 20x faster to my hd than to my usb stick...

April 10, 2010 6:54 PM

All ReadyBoost does is act as a cache so whenever you need to retrieve something it retrieves from the USB stick.

Duck musa
April 18, 2010 12:16 AM

I am using windows xp service pack 3 geniune version.I had downloaded eBoostr and add ram using my system hard drive.Before it was 504 mb ram now also it shows 504 mb ram when i click view system info it shows 504 mb ram only.Why is it?

September 2, 2010 1:05 AM

This is very helpful,

That's just a front end for ReadyBoost, which is NOT RAM.

Boris C.
April 23, 2011 7:21 AM

Doesn't flash memory have limited writes? Using it as virtual memory will wear it out faster.

December 17, 2011 11:58 AM

If the RAM stick is so slow. why are people putting whole operating systems like Linux on them and booting into them at startup?

Slower than RAM (MUCH slower to write), but faster than a hard disk. It's a way to have an operating system run on your machine without having to install it to the HD.
Lee Mcknight
April 10, 2012 10:29 PM

is there readyboost for windows xp and where can i find it.

Mark J
April 11, 2012 1:16 PM

Readyboost was a feature Windows implemented with Vista and it doesn't exist on XP.

July 10, 2012 5:39 AM

Can I use extra RAM memory in my nokiaE5,as has USB installed in it. Pls. Gaid me.
I hope help me.

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